High speed USB hub with full speed to high speed transaction translator

Abstract

High speed USB hub with full speed to high speed transaction translator. A USB hub may include an upstream port for coupling to a host and one or more downstream ports for coupling to downstream devices. The downstream devices may operate at USB high speed. The USB hub may support hosts which operate at speeds less than high speed (e.g., full speed). Accordingly, when a host operates at a lower speed, a transaction translator may convert the communications from the host from the lower speed to the high speed. Accordingly, the downstream device may still operate at high speed even when the host operates at a lower speed.

I claim: 
     
       1. system, comprising:
 at least one upstream port for coupling to a host; 
 at least one downstream port for coupling to at least one downstream device; 
 at least one transaction translator (TT) comprising one or more circuits and coupled to the at least one downstream port, wherein the one or more circuits are configured to: 
 split a communication received from the downstream device at the first speed into a plurality of packets when the host communicates at a second speed and does not support the first speed; 
 transmit an acknowledgment signal to the downstream device, wherein the acknowledgement signal is indicative of having received the communication and wherein the acknowledgment signal triggers an additional communication from the downstream device on the downstream port; 
 adjusting a toggle bit on at least one of the plurality of packets wherein the toggle bit is used by the host to confirm receipt of the plurality of packets; 
 adjusting a polling rate associated with the frequency of requests for communications from the downstream device; and 
 send the plurality of communications to the host device at a second speed wherein the second speed is slower than the first speed. 
 
     
     
       2. The system of  claim 1 , wherein the at least one upstream port, the at least one downstream port, and the at least one TT is comprised in a hub, wherein the hub is configured to operate at one or more of a USB full speed, a USB high speed, and a USB super speed. 
     
     
       3. The system of  claim 1 , wherein the at least one downstream device comprises a high speed inter-chip (HSIC) device. 
     
     
       4. The system of  claim 1 , further comprising:
 at least one first speed physical interface (PHY), wherein the at least one TT is interposed between the at least one first speed PHY and the host, wherein the at least one TT is not used when the host supports the first speed. 
 
     
     
       5. The system of  claim 1 , further comprising:
 an internal hub coupled to the at least one upstream port and the at least one TT; and 
 at least one first speed PHY, wherein at least one downstream port of the internal hub is coupled to the at least one first speed PHY and is separately coupled to the first speed PHY via the at least one TT; 
 wherein, when the host does not support the first speed, the at least one TT is configured to convert communications sent from the host via the at least one downstream port of the internal USB hub for the at least one first speed PHY; 
 wherein, when the host supports the first speed, internal hub is configured to provide the communications sent from the host to the first speed PHY without the at least one TT. 
 
     
     
       6. The system of  claim 1 . wherein, when the host supports the first speed, the at least one TT is configured to pass through communications sent from the host at the first speed to the downstream device. 
     
     
       7. The system of  claim 1 , wherein the second speed comprises USB full speed. 
     
     
       8. The system or  claim 1 , wherein the first speed comprises USB high speed. 
     
     
       9. The system of  claim 1 , wherein the one or more circuits are further configured to:
 aggregate a plurality of communications sent from the host at the second speed; and 
 send the aggregated communications to the downstream device at the first speed. 
 
     
     
       10. A method, comprising:
 determining whether a host supports a first speed or a second speed, wherein the first speed is higher than the second speed, wherein said determining is performed after connecting a hub apparatus to the host; 
 if the host communicates at a second speed and does not support the first speed:
 receiving a packet from a downstream device at the second speed; 
 splitting the communication received from the downstream device at the first speed into a plurality of packets; 
 sending a handshake signal to the downstream device wherein the handshake signal is indicative of having received the communication and wherein the handshake signal triggers an additional communication from the downstream device; 
 adjusting a toggle bit on at least one of the plurality of packets wherein the toggle bit is used by the host to confirm receipt of the plurality of packets; 
 adjusting a polling rate associated with the frequency of requests for packets from the downstream device; and 
 sending the packet to a downstream device at the first speed; 
 
 if the host does support the first speed:
 sending the packets to the downstream device at the first speed. 
 
 
     
     
       11. The method of  claim 10 , wherein said receiving, sending a handshake signal, adjusting, and sending the packet are performed by a second speed to first speed transaction translator. 
     
     
       12. The method of  claim 10 , wherein the host comprises a USB host configured to operate at a USB full speed and wherein the downstream device comprises a USB device configured to operate at a USB high speed. 
     
     
       13. The method of  claim 10 , wherein the downstream device comprises a high speed inter-chip (HSIC) device. 
     
     
       14. The method of  claim 10 , wherein said determining is performed by a hub configured to operate at one or more of a USB full speed, a USB high speed, and/or a USB super speed. 
     
     
       15. The method of  claim 14 , wherein the downstream device and the hub are comprised in a common device. 
     
     
       16. The method of  claim 10 , wherein the second speed comprises USB full speed, wherein the first speed comprises USB high speed. 
     
     
       17. The method of  claim 10 , wherein said sending the packet is performed by a first speed physical interface (PHY). 
     
     
       18. The method of  claim 10 , wherein said adjusting is performed by a second speed to first speed transaction translator (TT), wherein said sending the packet is performed by a first speed PHY, wherein the second speed to first speed TT is interposed between the host and the first speed PHY. 
     
     
       19. The method of  claim 10 , further comprising:
 receiving a packet from the downstream device; 
 splitting the packet into a plurality of smaller packets; and 
 sending the plurality of smaller packets to the host device at the second speed.